While flipping through the "Guinness Book of World Records" one night in January, Highcrest twins Luke and Ryan Novosel discovered the record for most sets of twins in a single grade was 16. Guinness recognized the ninth-grade class at Valley Southwoods Freshman High School in Des Moines, Iowa, last May.

The twins realized Highcrest's number of twins might exceed that record, and they immediately ran to tell their parents.

The twins' dad, Mike Novosel, looked through the school directory and counted 23 families with “5-5” after their names, denoting two children in the same grade, according to CBS Chicago.

Mike Novosel contacted the "Guinness Book" editors, who demanded proof in the form of birth certificates, school registrations, and a photo of all 46 children. The photo was shot Wednesday morning, and each set of twins wore the same color for the photo.

The Novosel twins’ mother, Nancy Fendley, said Guinness hasn't raised any red flags that would disqualify them from setting the record, but there are some oddities. All of the twins were born during the post-9/11 spike in births. Only one set of the 23 are believed to be identical; the rest are fraternal. One set was born on different days — a few minutes either side of midnight.

District 39 Superintendent Raymond Lechner told CBS he expects District 39 to update the record each year, if possible, as they move from Highcrest into Wilmette Junior High School.

The Novosels said they plan to resubmit for the record when the students arrive as freshmen at New Trier Township High School if other feeder schools from Wilmette, Glenview, Winnetka, Glencoe, and Northfield have their own sets of twins.

Between 1980 and 2009, the rate of twin births increased by 76 percent, according to the National Center for Health Statistics. About one in 30 babies born in the United States is a twin.